I want to know if the message stats reflect those who prefer text-only messages.

Esther Pomeleo-Fowler

The open rate does not include text emails. The reason for this is that Convio (and other senders) have no way of knowing when a text email is read - there is no feedback.

In an HTML email, the open rate is approximately known (but not absolutely) through the inclusion of a very small (1x1 pixel) transparent image in the message. This image carries a unique name/value for all emails so that the server knows that the image was opened when the pixel is requested. This is not fool-proof, however.  For example, MS Outlook opens emails without images turned on and not everyone dowloads the images when reading the email. Many users simply read the message in preview mode and don't even actually open it. For this reason, you need to think of your open rate in terms of trends... Are opens trending up or down? Was there new functionality in popular email software that may be behind the numbers? Etc.

On a related note, click-through rates are accurate and do count text messages.

Regarding the email preference numbers, the values are follows:

0 = UNDEFINED

1 = HTML

2 = PLAIN